I breed and sell xenia, blue and pink and I find some times it can be very picky about water flow. In my breeding tank I have very slow water movement and med. light. In my disp. tank It grows in all the sheltered areas way better. Try moving it close to one of those rocks. It doesn't need much light at all. My breading tank only has one 96watt 6700 compaq and it grows there beter than in my disp. with the hal.

OK so I guess I can't type in upper case. well these are my xenia. first pic is when I first bught them and second is a year later. my suggestion is to leave then in one spot. mid to upper level of the tank with a moderate water flow. xenia also filter feed off ammonia. AMMONIA can be very bad. but minute amounts will be OK. your xenia will thrive off of it. maybe add a fish or two. but carefull too much ammonia is toxic